mirror of
https://github.com/prometheus-community/postgres_exporter
synced 2025-04-17 12:35:26 +00:00
100 lines
2.8 KiB
Go
100 lines
2.8 KiB
Go
// Copyright 2023 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package collector
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import (
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"context"
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"github.com/go-kit/log"
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"github.com/prometheus/client_golang/prometheus"
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)
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const xidSubsystem = "xid"
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func init() {
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registerCollector(xidSubsystem, defaultDisabled, NewPGXidCollector)
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}
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type PGXidCollector struct {
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log log.Logger
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}
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func NewPGXidCollector(config collectorConfig) (Collector, error) {
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return &PGXidCollector{log: config.logger}, nil
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}
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var (
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xidCurrent = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, xidSubsystem, "current"),
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"Current 64-bit transaction id of the query used to collect this metric (truncated to low 52 bits)",
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[]string{}, prometheus.Labels{},
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)
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xidXmin = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, xidSubsystem, "xmin"),
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"Oldest transaction id of a transaction still in progress, i.e. not known committed or aborted (truncated to low 52 bits)",
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[]string{}, prometheus.Labels{},
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)
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xidXminAge = prometheus.NewDesc(
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prometheus.BuildFQName(namespace, xidSubsystem, "xmin_age"),
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"Age of oldest transaction still not committed or aborted measured in transaction ids",
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[]string{}, prometheus.Labels{},
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)
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xidQuery = `
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SELECT
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CASE WHEN pg_is_in_recovery() THEN 'NaN'::float ELSE txid_current() % (2^52)::bigint END AS current,
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CASE WHEN pg_is_in_recovery() THEN 'NaN'::float ELSE txid_snapshot_xmin(txid_current_snapshot()) % (2^52)::bigint END AS xmin,
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CASE WHEN pg_is_in_recovery() THEN 'NaN'::float ELSE txid_current() - txid_snapshot_xmin(txid_current_snapshot()) END AS xmin_age
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`
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)
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func (PGXidCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
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db := instance.getDB()
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rows, err := db.QueryContext(ctx,
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xidQuery)
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if err != nil {
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return err
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}
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defer rows.Close()
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for rows.Next() {
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var current, xmin, xminAge float64
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if err := rows.Scan(¤t, &xmin, &xminAge); err != nil {
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return err
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}
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ch <- prometheus.MustNewConstMetric(
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xidCurrent,
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prometheus.GaugeValue,
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current,
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)
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ch <- prometheus.MustNewConstMetric(
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xidXmin,
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prometheus.GaugeValue,
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xmin,
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)
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ch <- prometheus.MustNewConstMetric(
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xidXminAge,
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prometheus.GaugeValue,
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xminAge,
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)
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}
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if err := rows.Err(); err != nil {
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return err
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}
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return nil
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}
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